Pulmonary Valve Replacement After Operative Repair of Tetralogy of Fallot: Meta-Analysis and Meta-Regression of 3118 Patients From 48 Studies

Study Questions:

What is the impact of pulmonary valve replacement (PVR) on biventricular size and function, QRS duration, and functional status in patients with repaired tetralogy of Fallot (TOF)?

Methods:

A meta-analysis, sensitivity analysis, and meta-regression were performed in accordance with current guidelines. Studies were included if: 1) the study population included patients with repaired TOF with at least moderate pulmonary regurgitation; 2) patients were referred for PVR; 3) patients were assessed before and after PVR; 4) outcomes included any of the following: 30-day and 5-year mortality rates, 5-year redo-PVR rate, indexed right ventricular end-diastolic volume (RV-EDV), indexed RV end-systolic volume (RV-ESV), RV ejection fraction (RV-EF), corrected RV-EF, pulmonary regurgitant fraction, indexed left ventricular end-diastolic volume (LV-EDV), indexed LV end-systolic volume (LV-ESV), LV-EF, QRS duration, or New York Heart Association (NYHA) functional class.

Results:

Forty-eight studies involving 3,118 patients met the eligibility requirements. The pooled 30-day mortality was 0.87% (47 studies; 27/3,100 patients), whereas the pooled 5-year mortality was 2.2% (24 studies; 49/2,231 patients). The meta-analysis demonstrated a significant decrease in RV-EDV and RV-ESV, as well as QRS duration. There was an improvement in LV-EF. RV-EF improved when preoperative RV-EF was corrected for pulmonary or tricuspid valve regurgitation and residual shunts. There was no improvement in uncorrected RV-EF after PVR. NYHA functional status improved after PVR. Significant heterogeneity was seen between studies.

Conclusions:

The authors concluded that PVR has a positive impact on functional status and measures of biventricular size and function.

Perspective:

This meta-analysis looked at the outcomes of PVR in patients with repaired TOF. A decrease in RV volumes was seen across all studies. The effect was greatest in patients with larger ventricles, although interestingly, the patients with larger improvement in RV volumes showed less improvement in functional status. This may lend weight to the argument for intervening prior to development of significant RV dilatation. Individual studies have shown mixed results in terms of QRS duration; this meta-analysis demonstrated an overall decrease in QRS duration. The finding of improved LV systolic function after PVR is important and supports a role of ‘ventricular interdependence’ in the LV dysfunction sometimes seen in patients with repaired TOF. Finally, it is worth noting the findings of this study in relation to RV function. Although there was no difference in absolute RV-EF before and after PVR, a significant improvement was seen when preoperative RV-EF was corrected for pulmonary or tricuspid valve regurgitation. Use of corrected RV-EF may be considered when comparing pre- and postoperative imaging studies